Plate clamp or grapple



ay 25, 1942- s. "r. M LELLAN 2,284,006

PLATE CLAMP OR GRAPPLE Filed June 13, 1941 3 YWWM samum TMQLELLRN Patented May 26, 1942 I 7 PLATE CLAMP on GRAPPLE Samuel T. McLellan, South Charleston, W. Va... Application June 13,1941, Serial No. 397,959

7 Claims.

This invention relates to a lifting clamp or grapple for facilitating the handling of relatively heavy plate stock, angle shapes, beams and the like. In the handling of steel plate and the like by means of a grapple it is desirable that the grapple be capable of engaging and/or releasing the material in variouspositions, from the horizontal to the vertical, and it is also desirable that the gripping force exerted on the material being lifted be in proportionto or greater than the weight of the material; and it is an object of the present invention to provide a lifting clamp or grapple which will meet these requirements. 7

Another and more specific object of the invention is to provide a grapple particularly adapted for handling plate and analogous shapes utilizing a cam-shaped gripping jaw and, a coacting fulcrum member operating to exert a positive and tenacious grip on the plate throughout the lifting and carrying operation. V

Another object is to provide a grapple of the type specified incorporating a relatively few working parts which are well housed and pro.-

tected from damage through use and abuse and wherein side play and bending and shearing are substantially eliminated.

' A further object is to provide a lifting clamp or grapple which is safe in handling and may be easily and quickly applied and disengaged.

A still further object of the invention is to provide a lifting clamp or grapple which is of simple construction and therefore low in cost of manufacture and which at the same time is relatively light in weight yet unusually rugged and pos- .sessed of great strength and capable of with Figs. 5, 6 and 7 are views similar to 1,

showing the improved clamp or grapple in different plate-carrying and releasing positions.

Referring to the drawing in detail, the device comprises a housing made up of opposed plates 5 and 5' connected in fixed spaced relation by, a

series of rivets or studs 6, 6 6", 6 and 6 These plates are formed with a jaw recess 1 providing a space for the edge of the plate or other object to be lifted.

A stationary jaw 8, note Fig. 3, has a shank portion 8 mounted between the plates 5 and 5 along one edge of the recess 1, and a jaw portion 33* inserted in a-recess 8 formed in 'the plates at this point. This jaw maybe made in whole or in part of hardened steel with a roughened or knurled gripping surface. The' shank portion 8 is formed with a hole'or bore for insertion of a rivet or stud 9 and whereby the stationary jaw is firmlyyet removably secured in position. I I

A movable jaw H3 having a roughened and hardened gripping surface Ill is interposed between the plates5 and 5' opposite the sta tionary jaw B, the said movable jaw being-mounted by means of a pivot member or stud ll which is preferablyconstructed as shown in Fig. 4. This pivot member |l.(as well as certain other pivot members hereinafter referred to) has its opposite ends reduced in diameter, so that during the as sembling operation the plates 5 and 5' may be inserted over these reduced ends until they abut the shoulders Il provided by the enlarged diam--' eter of the centralportion of the stud.

The movable jaw l9 has a cam-shaped free end ll] adapted to engage in a jaw recess 12 formed in an actuator consisting of a fulcrum member 13 extending at an angle to the movablefjaw. This fulcrum member is mounted betweenjthe plates 5 and 5' by means of pivot pin or stud I4 which is preferably of the same construction as l the pivot member ,I l for the movable jaw Ill. ,The

outer end "of the fulcrum member l3 projects beyond the housing plates 5 and 5 and has pivotally connected thereto a yoke-shaped link It.

pivot member I6 for, said link being. also of the same construction asthe pivot members H and The movable jawzispreferably formed with a recess l 0 adapted to engage the stud or rivet 5' when the jaw isin retracted position, the said a stud thus providing a stop for the jaw.

In operation, the grapple is usually carried by a crane hook engaged in the-link It, the edge of the plate or other'object to be lifted being-received in the jaw space'l. i When the pull comes. on, the actuator or fulcrum member 13 is-rocked or rotated anticlockwise as viewed in. Fig. '1, thereby causing the movable jaw ll! to clamp the plate firmly against the stationary jaw 3,v the, gripping force increasing in direct relation to the weight of the plate being lifted. To release is provided and or suspended in a substantially perpendicular position.

In certain instances," it is convenient to release the plate when it attainsa substantially horizontal position of rest and Figure 6 illustrates how the grapple may behandled when 'it is desired to'deposit' a'plate in this manner, the lowering movement being from left to right: Figure- "I shows the position of the-grapple when it is desired to release a plateatan angle of substantially 2451. In' this instance the movement is from right to'left with respect to the plate,the fulcrum member 13 releasing the movable jaw Ill when the plate, coming'to rest on its supporting surface, attains an angle'of substantially 45.

It will thus be seen that the improved plate clamp or grapple will pick up steel plate in any position from the horizontal to the vertical and 1 lowerthe plate back to a horizontal'position;

and by reversing the position of thegrapplathe plate maybe picked up from the horizontal" to the'vertical and droppedor released from an angle of approximately 45". .In actual service,

it has been found that the gripping power of the grapple is at least four times the weight of the plate being lifted and has withstood overloads as much as 300%.

The parts of the improved-grapple are relatively few innumber and may be easily manufactured. In assembling the parts of the grapple, the housing plates 5 and 5' with thestationary jaw, movable jaw and actuator or fulcrum member mounted on their pivots, 7 may be brought together and the rivets 6 6 applied to hold the plates in definite spaced relation. I,

The grapple has marked durability and safety with relatively few wearing surfaces. The manper in which the plates 5 and 5' are mounted with respect to, the movable parts .ensures the eliminationof side play, and bending of the pivot members and shearing is practically impossible. The working parts are fully protected by the-- housing plates so that there islittle chance'of dama e from use or abuse.

It will be understood that certain minor changes in construction and design of the im- The grapple'is' not only capable of lifting platesbut will operate ing at an angle to the movable jaw.

3. A grapple for. lifting plate and likematerial comprising 7 cover plates cormected in definite spaced relation, said cover plates being formed with a recess providing a jaw space for the edge of an object to be lifted, a stationary jaw fixed between the cover plates at one side of said space and a movable jaw pivotallymounted' between said cover plates in opposed relationto the fixed jaw, said ,m'ovable jaw being 'provided with a cam-shaped freeend, a fulcrum member pivoted adjacent said movable jaw and having a recessed extremity into which. the cam portion of the movable jaw projects, said fulcrum member extending at an angle with respect to the movable jaw and whereby when a pull is exerted on the V fulcrum member the movable jaw ,is actuated into gripping relation with respect to the fixed jaw, and a suspension link pivotally connected to the outer end of the fulcrum member.

4. A grapple comprising cover plates connected together in definite spaced relation providing a 'housing,'said cover plates being formed with a recess defining a jaw space for the edge-of an object to-be lifted, a fixed jaw having'a shank tion of themovable jaw being provided with a gripping surface in opposed relation to the stationary jaw, the end of the movable jaw opposite its pivoted end being cam-shaped and projecting proved lifting grapple may bemade" without de parting fromthe spirit or scope of the invention as defined by the appended claims.

I claim: I 1. A grapple. comprisingapair of plates fixed in definite spaced relation and constituting a housing, said housing plates having ajaw recess therein to receive the edge'of' a plate or like object to be lifted, a movable jaw pivotally mounted between the housing plates adjacent said recess, one end of said jaw being cam'shaped, a fulcrum .member also pivotally mounted between said I housing plates and having a'jaw at one end engaging the cam portion of the movable jaw, and

a suspension link pivoted to the opposite end of the. fulcrum member.

2. A grapple for lifting plate and analogous material comprising ,cover plates connected'in definite spaced relation, said cover plates being 7 formed witha recess defining a jaw space for the edge-of an object to be lifted. a fixed jaw at free, a fulcrum member pivoted between said .cover plates and having a recessed extremity engaging the cam-shaped end of the movable jaw, said fulcrum'member occupying a position at an angle with respect to the movable jaw ,and whereby when apulll is exerted on the fulcrum member. the movable jaw is cammed against the object beingllifted. and a suspension link pivotally connected to, the opposite fulcrum member.

5. A grapple comprising a pair of cover plates, means connecting said plates in fixed spaced re lation providin a housing, said cover plates be ing formedwitha recess defining a jaw space for extremity of the one side ofv said jaw space and a movable jaw at the opposite. side of said jaw space, means pivotally mounted said movablejaw comprising a pivot member having its opposite ends reduced indiameter and its intermediate pivoting portion enlarged in diameter forming shoulders against which the opposed cover plates abut, the

I intermediate portion of the movable'jaw being provided with a gripping surface and the unpivoted end of the movable jaw'being cam-shaped, a fulcrum member pivotally mounted between said coverplates and extending at an angle to said movable'jaw and formed with a recess at one end into which the cam-shaped end of the movable jaw projects, and a suspension link connected to the opposite end of said fulcrum member.

6. A grapple comprising a supporting member formed with a recess defining a jaw space for the edge of an object to be lifted, a fixed jaw at one side of said jaw space and a movable jaw pivoted to said supporting member at the opposite side of said jaw space, the one end of said movable jaw projecting free, and a fulcrum member also pivoted to said supporting member and having one end engaging the free end of the movable jaw, said fulcrum member extending at an angle to said movable jaw and whereby when a pull is exerted on the fulcrum member the movable jaw 7. A grapple for lifting steel plate and like objects comprising a supporting member formed with a recess defining a jaw space for receiving the edge of an object to be lifted, a fixed jaw at one side of said jaw space and a movable jaw pivoted to said supporting member at the opposite side of said jaw space, said movable jaw being mounted for limited free movement about its pivot, and a fulcrum member also pivoted to said supporting member and having one end engaging said movable jaw, said fulcrum member extending at an angle to said movable jaw and whereby when a pull is exerted on the fulcrum member the movable jaw is cammed against the object being lifted.

SAMUEL T. McLELLAN. 

